It is well known that improving tire sidewalls with decorative lettering and designs is highly sought after in the marketplace for the purposes of aesthetic appearance, safety, product identification, tracking, branding and advertising. Traditional techniques for establishing tire sidewall markings involve extrusion or molding of black rubber and often the addition of colored inks which are cured in parallel with the tire during the vulcanization process. This process, though well established and scaled for industry, requires significant investment in materials, equipment and labor along with sizable wastage costs resulting from voids, blemishes and other defective designs.
In addition, this technique is extremely limiting in terms of customizable designs due to molds and dies required to achieve the desired variations and therefore the availability of this customization to individual consumers and even customers internal to the industry is extremely limited. Examples of appliqués or decals being co-cured with a green tire are found in U.S. Pat. Nos. 4,967,818 and 4,684,420. These methods for providing a decorative sidewall onto a tire add to the processing difficulty and expense of the tire, as discussed hereinabove.
The above mentioned difficulties have brought forth improved techniques for the application of decorative decals by way of a thermal transfer process to a cured tire. The technique of transferring a decal consisting of at least one layer of elastomeric ink with a temporary carrier sheet has been known as early as 1940 from U.S. Pat. No. 2,188,866 and continuously improved with consistent positioning techniques as mentioned in U.S. Pat. No. 6,080,465 as well as improved bonding of materials by way of the additional process step of applying adhesive layers to the tire sidewall prior to thermal transfer of thick, cured rubber articles cut in decorative shapes as disclosed in U.S. Pat. No. 5,300,164. None of the known decorative decals for vulcanized rubber products have reached wide-spread market acceptance. Consequently, there is a need for an efficient decorative decal for vulcanized rubber products that overcomes the deficiencies of the prior art.